Triple-negative　breast　cancer　(TNBC)　is　one　of　the　most　malignant　breast　cancers　lacking　targeted　therapeutics　currently.　We　recently　reported　that　mifepristone　(MIF),　a　drug　regularly　used　for　abortion,　suppresses　TNBC　cell　growth　by　inhibiting　KLF5　expression　via　inducing　miR-153.　However,　its　anticancer　efficacy　is　only　modest　at　high　dose.　In　order　to　enhance　the　anticancer　activities,　a　focused　compound　library　containing　17　compounds　by　altering　the　sensitive　metabolic　region　of　mifepristone　has　been　designed　and　synthesized.　We　first　tested　the　cell　growth　inhibitory　effects　of　these　compounds　in　TNBC　cell　lines.　Among　them,　FZU-00,003　displayed　the　most　potent　efficiency.　FZU-00,003　suppresses　TNBC　cell　growth,　cell　cycle　progression　and　induces　apoptosis　more　effectively　than　MIF　does.　Consistently,　FZU-00,003　induces　miR-153　expression　and　suppressed　KLF5　expression　at　much　lower　dosages　than　MIF　does.　Furthermore,　FZU-00,003　inhibits　tumor　growth　more　potently　than　MIF　does.　Taken　together,　the　MIF　derivative,　FZU-00,003　may　serve　as　a　better　therapeutic　compound　for　TNBC　than　MIF.　©　The　author(s).